The centrifuge tube is made of high-purity PP material, , no pyrogen, no DNAs/RNase, autoclavable at 121C/370F, freezer to -80C/-230F. The transparent exterior with high visibility allows you to easily view the samples inside, the 50ml centrifuge tubes are sterile with easy-to-read black scales from 5.0ml to 50ml in 2.5ml increments. The centrifuge tube also includes a large white writing area for easy marking and identification. The patches are great for marking, and the graduations and writing area are chlorine resistant. The centrifuge tube design has a longer screw cap with a sealing ring to prevent leakage. The lid can be tightly screwed onto the centrifuge tube, which has excellent sealing performance and effectively prevents liquid leakage. Smooth and flat inner surface, no residue solution. These centrifuge tubes are widely used in biochemistry and molecular biology, pharmacy and chemical laboratories, clinical diagnostic experiments, food science, etc. Color: As Shown Material: PP Package Contents: 1 set x 25 pieces test tubes with lids Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.